7^   .  ^r 


Circular  No  38,  Second  Rev 

United  States  Department  o(  Agriculture, 

BUREAU  OK   KNTOMOI.OGY. 


L.  O.   HOWARD.    KntomolouUt  and  CI. let  of  Bureau. 


I  III    sol   iSH-\  INK  HOKKR 

i  Milittiii  satiyriniformis  1 1 1  «i  i     ' 

I       II     i   ii :  i  i  i  m  •  I  \ 

D  iitul  Special  I 
3  DEPOSITORY 

vl'l'l.AR  \N<   I       \\  l>     MM  HOD    Ol      u«  'KK 

One  of  the  most  troublesome  of  the  man}  enemies  of  squashes, 
pumpkins,  and  other  cucurbits  is  the  squash-vine  Inner.  In  many 
localities  this Bpe- 
irpasses  all 
other  squash  in- 
Bects  in  point  of 
injuriousness. 

I  damage  is  due 
to  the  larvae  bor- 
ing through  the 
stems,  causing 
them  to  rot  at  the 
affected  points 
and  become  se^  - 
ered  from  the 
vine,  or  so  injur- 
ing the  vine  as  t" 
cause   the   leaves 


I'uish-virii-  Imt.t     m  Haiti  moth;  &. 

(•mate,  with  wings folded  own  on  brtol  *1 

./.  tan-grown  larva,  in  tUu  In  \  toe;  - .  papa;  /'.  pupal  ocD.    All  one-third 

larger  than  na(    -  «). 


to  \\  ill  and  the  plant  to  die.  The  presence  of  the  borer  feeding  within 
the  stem  is  not  apparenl  at  the  commencemenl  of  the  attack,  bul  soon 
becomes  manifest  through  the  presence  of  the  coarse  yellowish  excre- 
ment which  it  forces  from  its  burrow  in  the  stem  and  which  accumu- 
lates on  the  ground  beneath,  as  well  a<  by  the  sudden  \\  iltingand  dying 

down  .if  the  leave-.      Wilting  occurs  -non  after  the  larv;e  have  made 

early  publications  this  «p  rallyknoi 

d  ol  change  ol  Dame  see  writer-  article  in  Bul.  19,  n  b  .  \H\  Km.,  p 
Tlie  preeenl  edition  ,.i  t liis  circular  is  slightly  changed  from  the  original,  which 
published  April  22  od  ir->m  the  [first]  revised  edition    issued  November  if». 

51800     <  ir.  ::-     (»s 


2 

considerable  growth  within.  From  one  to  half  a  dozen  or  more  larvae 
inhabit  a  stem,  and  often  upward  of  forty  individuals  have  been  taken 
from  a  single  plant;  indeed,  one  grower  has  stated  that  he  once  cut 
"142  larvae  from  a  single  vine."  The  Larvae  work  with  great  rapidity 
and  in  a  very  short  time  are  able  to  injure  a  plant  so  that  no  fruit 
will  mature.  Injury  is  most  noticeable  near  the  base  of  the  stems, 
where  in  course  of  time  the  vine  becomes  severed  from  the  roots  and 
the  whole  vine  dies. 

Che  parent  of  'this  insect  is  a  beautiful  creature,  a  medium-sized 
moth  of  the  family  Sesiidae,  or  clear-winged  moths.  The  fore  wings 
are  opaque,  lustrous  olive-brown  in  color,  with  metallic  green 
reflections,  and  expand  from  less  than  an  inch  to  nearly  an  inch  and 
a  half.  The  hind  wings  are  transparent  and  veined  as  shown  in  the 
accompanying  illustration  of  the  male  (tig.  1,  a).  The  abdomen  is 
conspicuously  marked  with  orange  or  red.  black,  and  bronze,  and 
the  hind  legs  are  fringed  with  long  hairs — red  or  orange  on  the  outer 
surface  and  black  inside.  The  natural  position  of  the  moth  when  at 
rest  is  shown  by  the  figure  of  the  female  (b).    . 

DISTRIBUTION. 

As  far  as  known,  the  squash-vine  borer  is  a  native  of  the  Western 

Hemisphere,  and  widely  distributed  and  injurious  in  the  United 
States  practically  wherever  squashes  are  cultivated.  Available  rec- 
ords and  examination  of  material  in  the  collection  of  the  l".  S.  National 
Museum  show  that  it  has  a  range  embracing  territory  from  the  Xew 
England  States  and  Canada,  in  the  north,  to  the  Gulf  States  south- 
ward, and  westward  to  the  region  beyond  the  Missouri  River,  which 
comprises  the  major  portion  of  the  Carolinian  and  Austroriparian 
areas  of  the  Upper  and  Lower  Austral  life  zones  and  a  portion  also  of 
the  Transition  zone.  Injury  has  been  observed  to  be  particularly 
severe  in  recent  years  on  Long  Island  and  in  New  Jersey.  Delaware, 
Maryland,  Virginia,  and  the  District  of  Columbia,  in  the  East,  and  in 
Kansas  and  Nebraska  in  the  West.  Other  States  in  which  injury 
has  been  noted  include  Maine.  Massachusetts.  Connecticut,  Rhode 
Island,  Georgia,  Alabama.  Mississippi.  Louisiana,  [owa,  and  Michi- 
gan. It  is  evidently  of  tropical  origin,  and  occurs  in  Mexico,  where 
it  is  also  widely  distributed,  and  in  Guatemala.  Panama.  Venezuela, 
Argentina,  and  the  Lower  Amazon. 

FOOD    HABITS. 

The  vines  of  squash  and  pumpkin  form  the  chief  food  supply  of 
this  insect,  but  occasionally  it  attacks  also  the  gourd,  muskmelon,  and 
cucumber.  It  does  not,  however,  in  the  writer's  experience,  infest 
melons  and  cucumbers  when  the  other  preferred  crops  are  available. 
The  larvae  bore  through  the  stems  from  the  roots  to  the  base  of  and 

[Cir.  38] 


even  through  the  leaf-stalks,  and  young  larva;  ma}  be  found  even  in 
the  larger  veins,  into  which  the}  !►•  >n-  when  the  eggs  have  been  placed 
in  mii  h  locations,  and  often  attack  the  fruit.  The}  also  penetrate 
gourds  so  hard  thai  it  is  difficult  to  cut  into  them  with  a  sharp  knife 
Larvae  have  been  observed  on  the  wild  balsam  apple  (Echinocy 
lobata),  which  isprobabl}  a  natural  t"<  >.  ><  1  plant. 

Injur}  i-  greatest  to  Hubbard,  marrow  cymlings,  and  other  lut «■ 
varieties  of  squash,  and  is  apt  to  he  more  acutely  Mi  in  small  gardens 
than  where  crops  arc  grown  for  market.  Even  if  the  plant  survives 
tit  tack  it  may  not  hear  fruit .  and  often  the  grower  loses  a  large  propoi 
tion  of  his  crop  year  after  year.  Not  infrequently  entire  crops  are 
destro}  ed. 

\  \  i  i  i:  \i     HISTi  >i:i  . 

This  species   i>  injurious  onl}    in   the  larval   form.     Although   the 
lar\;c  arc  familiar  objects  to  squash  growers,  the  moths  arc  not  genei 
all}  recognized  as  t  he  parents  of  t  hese  pernicious  borers. 

The  moths,  unlike  most  others,  ll\  onl}  during  the  daytime  and  in 
the  heat  of  the  da}  .  Tov«  ard  t  w  ilight  they  become  less  act  i\  e  and  ma} 
be  seen  sitting  quietl}  on  the  leaves  of  their  host  plants.  Both  when 
in  flight  and  when  at  rest  the  moth-  arc  Bingularl}  wasp-like  in 
appearance. 

Timt  of  appearand  <>i  tl>>  moth.  Approximate!}  it  ma}  be  stated 
t hat  the  moth  appears  as  soon  a-  the  \  ines  are  sufficientl}  advanced  to 
serve  for  oviposition  and  the  subsequent  subsistence  of  the  borer  larvae 

within  their  stems.  Indications  are  t  hat  a-  far  south  a-  t  he  Dist  riet  of 
Columbia  the  moths  make  their  first  appearance  in  the  held  some  time 
in  May,  or  at  leasl  earh  in  June,  a-  larvae  aearrj  matured  have  been 
found  by  the  middle  of  July.  In  New  Jersey,  according  to  Dr.  J.  B. 
Smith,  the  moth-  arc.ahroad  at  or  soon  after  the  beginning  of. lime; 
on  Long  Island,  from  the  middle  to  the  last  of  June. .  In  Massachuset  t-. 
according  to  Harris,  they  appear  about  the  plants  the  second  week  in 
July.  We  thus  have  considerable  variation  in  time  of  earliesl  appear- 
ance, dependent  upon  season  and  localit}  a  variation  to  he  expected  in 
a  species  of  so  wide  a  range. 

egg  ami  oviposition.  The  eggs,  which  are  oval  and  dull  red  in 
color,  are  laid  upon  all  part-  of  a  plant,  from  the  root-  to  the  hud-  and 
petiole-,  hut  chief!}  along  the  stems,  although  in  some  varieties  of 
squash,  il  i-  -aid.  nearer  the  base  of  the  stem  than  otherwise.  Ovi- 
position i-  very  rapid,  the  moth  flitting  from  hill  to  hill,  leaving  an 
in  each.  A  single  moth  ma}  la}  as  man}  as  212  eggs.  The  eggs  hatch 
m  from  -i\  to  fifteen  day-  after  the}  are  deposited,  and  the  larvae  are 
-aid  to  attain  full  growth  four  or  more  week-  later.  This  period  will 
undoubtedl}  vary  in  differenl  temperatures,  according  to  the  season  of 
the  year  when  oviposition  take-  place. 


Eggs  arc  shown  a  little  larger  than  natural  at  c  of  figure  1,  and  much 
magnified  at  a  and  h  of  figure  2,  c  showing  the  sculpture. 

1  %  larva. — The  larva  is  a  soft,  whitish,  grub-like  caterpillar  of  nearly 
cylindrical  form,  with  a  small,  dark  head  and  a  few  very  sparse  hairs 
on  each  segment.  Larvae  in  the  earlier  stages  of  growth  arc  illus- 
trated by  (I,  e,  and/ of  figure  2.  A  full-grown  larva  is  shown  in  profile 
within  an  open  stem  at  figure  1.  d,  and  the  head  and  first  two  thoracic 
segments  appear  in  figure  2  at  g.  Mature  larvae  measure  about  an  inch 
(25  mm  in  length).  In  the  District  of  Columbia  full-grown  larvae,  as 
already  observed,  occur  as  early  as  July  1G;  in  Xew  Jersey,  later  in 
July,  and  are  to  be  found  upon  the  vines  in  different  stages  in  October; 
at  Washington,  as  late  as  the  second  week  of  November. 

After  attaining  maturity  the  larva'  desert  the  stems  and  enter  the 
earth,  burying  themselves  to  the  depth  of  1  or  2  inches,  and     form 

their  cocoons,  in  which 
the}  transform  to  pupae. 
Theoocoon  (fig.  1,/)  is  con- 
structed of  silk  and  coated 
externally  with  fine  parti- 
cles of  earth ,  which  adhere 
< in  account  of  somegummy 
secretion  of  the  larva. 

Tht  pupa  or  chrysalis 
(shown  in  profile  at  e,  fig. 
1  measures  about  §  inch 
in  length  (16  mra).  It  is 
shining  mahogany  brown 
incolorand  its  head  isorna- 
mented  in  front  just  above 
and  between  the  eyes  with 
a  horn-like  process.  By  means  of  this  the  pupa  cuts  its  way  out  of 
one  end  of  its  cocoon  and  by  the  aid  of  the  abdominal  hook-like  spines 
forces  itself  to  the  surface  of  the  earth  before  transforming  to  adult. 
Number  of  generations. — The  question  of  the  number  of  generations 
produced  annually  in  localities  of  different  temperatures  which  this 
insect  inhabits  has  been  solved  by  actual  observation,  the  results  serv- 
ing to  indicate  that  it  is  practically  single-brooded  on  Long  Island  and 
northward:  that  there  is  a  tendency  to  two  broods  in  Xew  Jersey,  the 
moths  in  exceptional  cases  completing  their  transformations  late  in 
August  or  September;  that  in  the  latitude  of  the  District  of  Columbia 
the  species  is  partially  double-brooded,  a  larger  portion  of  the  moths, 
we  may  assume,  developing  as  a  second  generation  here  than  in  Xew 
Jersey;  and  that  in  the  Gulf  States  this  series  is  undoubtedly  fully 
two-brooded. 

[Cir.  38] 


Fig.  2. — Squash-vine  boier*(Melittia  satyriniformis):  a,  Egg 

as  seen  from  above:  //.  same  from  the  side,  showing  sculp- 
ture; r,  sculpt  ure  of  egg,  greatly  enlarged;  <l.  newly  hatched 

larva;  c.  half-grown  larva;  /.  head  of  same  from  side:  g> 
head  of  mature  larva  from  above:  o,  b,  and  ,  ,  much  en- 
larged: d.  e.f.  and  g,  less  enlarged  (author's  illust  ration  I . 


I •  I :  I  \  RNTIV1      \  M>    1:1  \i  mm  \  I     MEASUB1 

This  borer  is  on  exceptionally  difficult  insect  to  control,  as  ordinary 
insecticides  are  of  no  value  after  the  insect  has  once  entered  the  vines, 
and  repellents  are  also  practically  useless.  We  are,  therefore,  depend- 
ent upon  cultural  methods  for  relief. 

Knowing  thai  the  insecl  passes  the  winter  in  the  fields  which  it  has 
ravaged,  it  should  be  superfluous  to  caution  growers  against  planting 
squashes  in  the  same  ground  in  successive  years. 

Early  squashes  as  traps.  Qood  results  have  been  obtained  l>\  plant- 
ing as  a  trap  crop  and  as  eariy  a-  possible  a  feu  summer  squashes, 
such  a-  crooknecks  and  early  cymlings,  before  and  between  rows  "i 
the  main  crop  of  late  varieties.  The  summer  squashes  attract  the 
insects  in  such  numbers  a-  t<>  leave  a  smaller  number  t"  deal  with 
upon  the  late  or  main  crop.  As  soon  a-  the  earlj  crop  i-  gathered,  or 
earlier  if  the  ground  i-  needed  lor  the  main  crop,  the  \  inesare  promptly 

raked  up  and  hurtled   to  destroy  all  eggs  and  larva'  which  they   nia\ 

harbor,  and  the  same  treatment  i-  followed  alter  gathering  the  late 
varieties.  This  method,  according  to  Dr.  J.  B.  Smith,  has  proved 
profitable  where  used  in  New  Jersey,  and  should  produce  good  results 
farther  north.  Southward, where  two  well-defined  broods  appear,  it 
might  not  be  so  productive  of  good,  hut  it  should  be  given  a  thorough 
test. 

Fall  harrowing  and  deep  spring  plowing.  Experiments  conducted 
hv  .Mr.  I'-.  A.  Sirrine.  of  the  New  York  Agricultural  Experiment  Station 
at  Geneva,  N.  Y..  -how  that  this  species  can  he  greatly  reduced  l>\ 
lightly  harrowing  the  surface  of  infested  squash  fields  in  the  fall  so  as 
to  bring  the  cocoons  of  the  vine  borer  t<>  the  surface,  where  they  will 
he  exposed  to  the  element-,  and  then  plowing  in  the  spring  to  a  uni- 
form depth  of  at  lea-t  6  inches,  80  that  the  adult-  will  not  he  able  to 
issue. 

Other  cultural  methods.  When  the  vines  have  attained  some  length 
parts  of  them  should  be  covered  over  with  earth,  so  that  secondary  roots 
will  he  sent  out  to  support  the  plant-  in  case  the  main  root  i-  injured 
by  the  borer.  Keeping  the  plants  in  good  condition,  free  from  other 
insects  and  from  disease,  and  well  nourished  with  the  assistance  of 
manure  or  ot  her  fert  ili/.er  if  necessary,  w  ill  also  aid  t  he  plant-  to  with- 
stand borer  attaek.  When  vines  are  30  badly  infested  a-  to  he  incapa- 
ble of  bearing  fruit  they  usually  die  at  once,  and  they  should  then  he 
promptly  taken  out  and  burned.  The  old  vine-  should  also  ho 
destroyed  as  soon  as  the  crop  is  made. 

Cutting  <»it  tin  borers.  The  old-time  remedy  of  cutting  the  borers 
out  of  the  vine-,  although  laborious,  i-  useful,  and  about  the  only 
method  open  for  employment  after  they  have  entered  the  vines.  As 
several  individuals  often  infest  a  single  vine,  it  i-  best  to  cut  longitudi- 

[Or 


nally,  so  as  not  to  sever  the  vine  from  the  root  stalk.  If  the  wound 
made  by  cutting  be  afterwards  covered  with  moist  soil  it  will  assist  it  to 
heal.  The  location  of  the  horer  in  the  vine  can  he  readily  detected  by 
the  accumulation  of  its  yellow  'Trass"  or  excrement  at  the  point  where 
it  is  working,  and  which  is  kepi  open  for  the  extrusion  of  this  matter. 

i  'apturing  /In  moths. — This  species  may  he  held  in  partial  subjection 
by  keeping  a  sharp  lookout  for  the  parent  moths,  which  are  readily 
seen  and  not  difficult  of  capture  toward  dusk  or  in  the  cool  of  the 
morning,  when  they  are  comparatively  inactive.  The  female  may 
then  he  easily  caught,  just  as  she  alights  on  a  vine  for  oviposition." 
Several  persons,  including  the  writer,  can  vouch  for  this  statement. 

Summary. — If  the  grower  would  make  certain  of  securing  a  good 
crop  in  localities  where  this  and  other  enemies  of  the  squash  occur  in 
their  most  destructive  abundance,  it  will  be  necessary  for  protection 
against  this  horer  to  observe  most  of  the  following  precautions,  and, 
if  possible,  secure  the  cooperation  of  his  neighbors  in  their  observance: 

(1)  Not  to  plant  in  or  near  infested  ground. 

(2)  To  plant  early  varieties  for  the  protection  of  late  squashes. 

(3)  To  harrow  infested  fields  lightly  in  fall  and  plow  deeply  in  spring, 
to  prevent  the  moths  from  issuing. 

(4)  To  encourage  the  growth  of  secondary  roots  by  covering  the 
stems  with  earth. 

(5)  To  destroy  dead  vines  and  old  plants  as  soon  as  the  crop  is 
made. 

(6)  To  keep  the  plants  in  vigorous  condition,  free  from  other  insects 
and  disease. 

(7)  To  cut  out  such  borers  as  may  succeed  in  entering  the  vines  in 
spite  of  the  employment  of  other  remedial  measures. 

The  capture  of  the  moths  before  egg  deposition  is  also  advisable. 

Approved : 

James  Wilson, 

Secretary  of  Agriculture. 

Washington,  D.  C,  July  17,  1908. 

"As  additional  proof  of  the  practicability  of  this,  the  writer  refers  to  the  testi- 
mony of  Mr.  .].  Y.  I).  Walker  in  Insect  Life  (Vol.  IV.  pp.  L'71.  272 

[Cir.  38] 

o 


UNIVERSITY  OF  FLORIDA 


3  1262  09216  4515 


I 


